Facial emotion recognition, an important part of human-computer interaction and affective computing researches, relates to the research fields of psychology, sociology, anthropology, life sciences, cognitive sciences, computer sciences and the like and is significant for intelligent and harmonious human-computer interaction.
The internationally renowned psychologist Paul Ekman and his research partner W. V. Friesen made a thorough research to describe corresponding relationships between different facial muscle actions and different expressions by observation and biofeedback. Facial action coding system (FACS) is a facial action coding system created in 1976 after years of researches. According to an anatomic characteristic of a face, the face may be divided into a plurality of AUs which are mutually independent and also mutually associated and motion features of these AUs and main regions controlled by them may reflect facial expressions.
At present, a method for recognizing an AU feature in a facial image to judge a facial expression is relatively common and relatively high in accuracy. However, AU feature recognition in the industry is mostly implemented by collecting a great number of AU samples, arranging and dividing the samples into several types and training an AU feature recognition model by use of a convolutional neural network for AU feature recognition. This method is not so accurate.